Hook structure of a soft hook strap of a hook-and-loop fastener

ABSTRACT

An improved hook structure, of a soft hook strap of a hook-and-loop fastener, has a width W and includes: a hook body integrally protruding upright from a substrate of the hook strap; and a curved head portion curvedly bent downwardly from a top end of the hook body, the head portion including a hook end and a neck portion extending between the hook body and the hook end, wherein a lower side of the neck portion has a curvature defined by an imaginary circle located in a space between the hook body and the hook end and the head portion has a height H defined by points A and B on head portion which are intersection points of a imaginary vertical line passing through the center of the circle intersecting with an upper side and the lower side of the head portion respectively. The width W of the hook structure and the height H of the head portion satisfies a relationship defined below: 
     
       
         
           
             0.1 
             &lt; 
             
                
               
                 1 
                 - 
                 
                   H 
                   W 
                 
               
                
             
             &lt; 
             
               0.3 
               .

FIELD OF THE INVENTION

The present invention relates generally to hook-and-loop fasteners, and more specifically, to an improved hook structure of a soft hook strap of a hook-and-loop fastener.

BACKGROUND OF THE INVENTION

A hook-and-loop fastener (also known as ‘Velcro’) is a well know mechanical fastener and wildly used in a variety of fields that need to fasten two separate parts together, such as garment, shoes, personal care product (such as diapers) etc., because of its easy engaging/disengaging features. The hook-and-loop type fastener mainly consists of a hook strap on which an array of hooks are formed and a loop member on which a plurality of loops are formed to be engage with the hooks of the hook strap. In order to be applicable to different applications, the design of the hook-and-loop fastener (especially, the hook strap) has to be modified to meet specific requirements of a specific application.

For instance, in the field of clothing and garment, the hook straps used on the clothing/garment need to have sufficient suppleness to comply with the soft and flexible nature of the clothing/garment while providing the expected fastening/fixing function of the hook-and-loop fastener. Additionally, in the field of diapers, because the hook strap used on a diaper as a fastening means to fasten the diaper on a wear is in direct contact with wear's skin, thus if the hook strap does not have sufficient suppleness, the wearer of the diaper may feel uncomfortable and may even leave a mark on the skin of the wearer.

Therefore, it is a long existing challenge in the field of hook-and-loop fastener to provide a hook strap which can exhibit proper suppleness while providing fastening function with characteristics such as being able to engage the loops firmly, having sufficient engaging strength, having robust hooks that are not easily to break so as to extending the service life.

SUMMARY OF THE INVENTION

The inventor of the present invention realizes that using a material having a proper softness and flexibility to form the hook strap is a key factor to allow the hook strap to have a required suppleness, and on top of that a proper design of the hook structure of the hook strap is another key factor that would remarkably affect the suppleness of the hook strap. After a long term research performed by the inventor of the present invention, the inventor of the present invention concludes that the above-mentioned long existing challenge in the field of hook-and-loop fastener can be properly addressed by providing a hook structure having a head portion with carefully and specially designed dimensions so that the hooks of the hook strap are able to properly engage with the loops of a loop strap so as to prevent undesired stress concentration from occurring on the hooks and in turn prevent premature breakage of the hooks and the loops to give the hook strap a long service life while maintaining a proper suppleness of the hook strap.

According to the conclusion of the research, an improved hook structure of a soft hook strap of a hook-and-loop fastener is provided. The improved hook structure has a width W and comprises:

a hook body integrally protruding upright from a substrate of the hook strap; and

a curved head portion curvedly bent downwardly from a top end of the hook body, the head portion including a hook end and a neck portion extending between the hook body and the hook end, wherein a lower side of the neck portion has a curvature defined by an imaginary circle located in a space between the hook body and the hook end and the head portion has a height H defined by points A and B on head portion which are intersection points of a imaginary vertical line passing through the center of the circle intersecting with an upper side and the lower side of the head portion respectively,

the improved hook structure being characterized in that the width W and the height H of the head portion satisfy a relationship defined below:

$0.1 < {{1 - \frac{H}{W}}} < {0.3.}$

According to one embodiment of the present invention, the hook structure of a soft hook strap of a hook-and-loop fastener is formed of a material containing about 40 wt % of Nylon and about 60 wt % of elastomer.

Features and advantages of the present invention other than the above will become clear by reading the description of the present specification with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic perspective view showing an improved hook structure of a soft hook strap of a hook-and-loop fastener according to one embodiment of the present invention; and

FIG. 2 is a schematic plane view showing a front view of the improved hook structure of a soft hook strap of a hook-and-loop fastener shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to embodiments illustrated in FIGS. 1 and 2 to describe an improved hook structure 10 of a soft hook strap of a hook-and-loop fastener of the present invention.

FIG. 1 is a schematic perspective view showing the improved hook structure 10 of a soft hook strap of a hook-and-loop fastener according to one embodiment of the present invention. The improved hook structure 10 of a soft hook strap of a hook-and-loop fastener has a width W and comprises: a hook body 12 integrally protruding upright from a substrate 11 of the hook strap; and a curved head portion 14 curvedly bent downwardly from a top end of the hook body 12. The head portion 14 includes a hook end 16 and a neck portion 18 extending between the hook body 12 and the hook end 16. A lower side of the neck portion 18 has a curvature defined by an imaginary circle located in a space between the hook body 12 and the hook end 16. The head portion 14 has a height H defined by points A and B on the head portion which respectively are intersection points of a imaginary vertical line L passing through the center C of the circle and intersecting with an upper side and the lower side of the head portion 14. Preferably, point A is the highest point of the hook structure 10. Preferably, the width W of the hook structure 10 and the height H of the head portion 14 satisfy a relationship defined below:

$0.1 < {{1 - \frac{H}{W}}} < {0.3.}$

According to a preferred embodiment of the present invention, the hook structure 10 of a soft hook strap of a hook-and-loop fastener is formed of a material containing about 40 wt % of Nylon and about 60 wt % of elastomer.

Although the present invention has been described above according to a preferred embodiment illustrated in the accompanying drawings, this does not mean that the scope of the present invention is limited to specific configurations of the hook structure 10 of a soft hook strap of a hook-and-loop fastener described above. It will be apparent to people skilled in this art that many modifications can be made to the disclosed structures without departing from the true scope of the invention defined by the appended claims. Therefore, it is the intent of the appended claims to cover all such variations and modifications as come within the sprit and scope of this invention. 

1. An improved hook structure of a soft hook strap of a hook-and-loop fastener having a width (W) and comprising: a hook body integrally protruding upright from a substrate of the hook strap; and a curved head portion curvedly bent downwardly from a top end of the hook body, the head portion including a hook end and a neck portion extending between the hook body and the hook end, wherein a lower side of the neck portion has a curvature defined by an imaginary circle located in a space between the hook body and the hook end and the head portion has a height (H) defined by points (A) and (B) on the head portion which are intersection points of an imaginary vertical line passing through the center of the circle intersecting with an upper side and the lower side of the head portion respectively, the improved hook structure being characterized in that the width (W) hook structure and the height (H) of the head portion satisfy a relationship defined below: $0.1 < {{1 - \frac{H}{W}}} < {0.3.}$
 2. The improved hook structure of a soft hook strap of a hook-and-loop fastener according to claim 1, wherein the hook structure is formed of a material containing about 40 wt % of Nylon and about 60 wt % of elastomer. 